Such valve devices are known, for example, from the context of secondary air supply for the control of the volume of secondary air introduced into the exhaust gas system, whereby the pollutant emissions in the exhaust gases of the internal combustion engine can be reduced by the oxidization of non-combusted hydrocarbons. These valves comprise a valve, often actuated electromechanically, by means of which the amount of air is regulated, as well as a check valve which prevents a reverse flow of exhaust gases towards the secondary air pump due to exhaust gas pulsations. For a detection of malfunctions of the secondary air pump or for the control of the secondary air supply, it is known to arrange a pressure sensor in the channel leading to the valve device. However, this sensor requires additional electric connections and additional structural space.
In an attempt to solve this problem, DE 10 2005 011 884 A1 describes a valve device for a secondary air supply system in which a secondary air pump introduces secondary air into an exhaust gas pipe at a point upstream of a catalytic converter in order to accelerate the heating and the activation of the catalytic converter. A valve device is provided between the secondary air pump and the exhaust gas pipe, which valve device comprises a fluid inlet channel and a fluid outlet channel that is connected with the exhaust gas pipe, the amount of air flowing from the fluid inlet channel to the fluid outlet channel being dependent on the position of the valve. For a reduction of structural space, the pressure sensor of this embodiment is arranged above the electromagnet of the valve. The connection of the pressure detection chamber, in which the pressure sensor is arranged, with the fluid inlet channel is effected via narrow gaps along the coil of the electromagnet. However, the available cross sections are very small in this instance so that the measuring results reflect reality only with a delay. Pressure losses also occur due to the small cross sections so that overall inaccurate measurements result.
In order to obtain measuring results as accurate as possible in real time, DE 10 2007 000 900 A1 describes providing openings at the fluid inlet channel that are connected with a pressure measuring chamber housing a pressure sensor. In this arrangement, the air flows towards the pressure sensor, i.e., the pressure detection surface is directly opposite the channel. This is supposed to allow for very exact pressure measurements, with the pressure detection accuracy being maintained even if a so-called impact or shock wave should appear at the fluid inlet. However, this kind of arrangement is disadvantageous in that, in particular, the fluid inlet requires considerable structural space, since the additional pressure detection space with the associated pressure sensor must be provided, respectively. The variability of such a valve with respect to the adaptation to different structural spaces is moreover very restricted, in particular with respect to the adaptation of the connector position. In controlling the valve, short pressure pulsations may cause a faulty control of the valve.